scale question

[aferguson]

i've always been told and it seems intuitive, that when viewing a scale model it appears to be the scale times the distance away from you.

In other words, if you look at a 1/18 scale plane, that is sitting 10 feet away, that is the same as looking at the full scale plane from 180 feet.

I've been pondering this though and i'm wondering if that is completely correct. From my limited knowledge of perpsective drawing i know that circles and squares are usually drawn distorted as elipses and trapezoids, in order to make them look proper in a perspective drawing. However that is two dimensional and models are 3 dimensional.

I'm fairly certain that viewing a scale model is exactly the same as viewing the full size model at the scale times the distance but just want some confirmation of this.

[RAD 2112]

I have never heard of that before... and I use scales on a daily basis.

Model Scales

"Aircraft can be modeled at many scales. Popular scales are, in order of size, 1:144, 1:72 (the most numerous), 1:48 (sometimes referred to as quarter scale because a quarter inch represents one foot) 1:32 and 1:24."

1:18 Scale

1:18 scale is a common reference to Diecast Replicas that are 1/18th the size of the real thing

[aferguson]

yes it is correct. I just verified it using similar triangles. High school geometry to the rescue.

So, viewing a 1/x scale model at y feet is the same as viewing the full size thing a xy feet. For example viewing a 1/18 model at 10 feet is the same as viewing the full size thing a 18 x 10 = 180 feet. By same i mean it looks the same size.

Another example: viewing a 1/72 scale model at 3 feet is the same as viewing the full sized thing at 72 x 3 = 216 feet.

[RAD 2112]

I can see where you're coming from on the distance angle... pardon the pun.

But to keep it simple, 1:18 scale just means it's 18x smaller than the original.

[art2614]

Well, what if you squint your eyes? Does that make it seem farther?

[grockwood]

That is an interesting concept. While reading accounts of tank battles at different distances, I have wondered what a tank at say 500 meters away looked like. How easy was it to indentify and such.

[aferguson]

RAD.......yes i know that 1/18 means it's 18X smaller than the original. That wasn't what i was wondering about in this thread. I was wondering about the distance/size correlation between a scale model and the full size subject. It seemed intuitively obvious but sometimes things like that aren't. eg is a wing moving through the air at 200mph the same as air flowing over a wing at 200mph.

The answer is yes but it took testing to determine that.

This was kind of the same type of problem in my view. It seemed like a 1/18 object sitting 10 feet away should appear the same as the full size object would at 180 feet, but there could have been some other factor to consider. Then i thought of using similar triangles and was able to prove it was as simple as it seems.

[cranedriver]

yes it is correct. I just verified it using similar triangles. High school geometry to the rescue.

So, viewing a 1/x scale model at y feet is the same as viewing the full size thing a xy feet. For example viewing a 1/18 model at 10 feet is the same as viewing the full size thing a 18 x 10 = 180 feet. By same i mean it looks the same size.

Another example: viewing a 1/72 scale model at 3 feet is the same as viewing the full sized thing at 72 x 3 = 216 feet.

So basically if i put a 1:18 tank on a table and hung a 1/72 plane coming in to strafe 3ft away and took a picture from behind the commander sitting in the cupola it would give the same persepctive as a tank commander seeing a diving plane at 216 feet away coming in for a attack.

Cool.

I think I rember Red doing this in some of his dios with some smaller scale planes.

[aferguson]

well you have to be careful. The distance impression is from your viewpoint (ie where your eyeballs are) not from the model.

if you back up from that tank/plane piece then the distances change. If you're 3 feet from the tank it looks 54 feet away from you and the plane will look to be 432 feet from you and thus 432-54=378 feet behind the plane.

The other problem is that the brain realizes that it's a little model a few feet away, using visual cues in the room, depth perception etc and it sort of kills the effect a bit. I find looking with just one eye helps, as it dampens your depth perception.

Certainly a photograph would look good though, if lined up properly. Red used a 1/144 hellcat i believe.

[skypirate]

I've been pondering this though and i'm wondering if that is completely correct. From my limited knowledge of perpsective drawing i know that circles and squares are usually drawn distorted as elipses and trapezoids, in order to make them look proper in a perspective drawing. However that is two dimensional and models are 3 dimensional.

I'm fairly certain that viewing a scale model is exactly the same as viewing the full size model at the scale times the distance but just want some confirmation of this.

One exception would be depth of field. Photographing a scale model, it's easy to overlook the depth of field and have optical qualities that would be impossible/unnatural at full size.

Take a look at Flickr's Fake DoF pool and you'll see life size objects that look like toys because they've applied an unnaturally shallow depth of field. Personally, I don't like gimmicky stuff like that (and plenty of them don't know what they're doing, lots of mental errors in their logic), but it does demonstrate how profoundly depth of field can subconsciously influence our sense of scale.

[RAD 2112]

RAD.......yes i know that 1/18 means it's 18X smaller than the original.

My apologies, I misread your original post.
Yesterday was a long day.

Speaking of long days... I need more coffee...